diff --git a/src/strategy_team/strategy_003.rs b/src/strategy_team/strategy_003.rs
index e60b2a3..a5fac0d 100644
--- a/src/strategy_team/strategy_003.rs
+++ b/src/strategy_team/strategy_003.rs
@@ -175,7 +175,61 @@ pub async fn list_up_for_buy(
     }
     try_join_all(task_vec).await?;
 
-    let final_filtered_data = filtered_data_3rd_arc.lock().await.clone();
+    // 4th filtering: BollingerBand (len:20, multiplier 2) 5 previous_30m_price (close or low price) < lower_band
+    let filtered_data_3rd = filtered_data_3rd_arc.lock().await.clone();
+    let mut filtered_data_4th: Vec<FilteredData> = Vec::new();
+    let mut filtered_data_4th_arc: Arc<Mutex<Vec<FilteredData>>> =
+        Arc::new(Mutex::new(filtered_data_4th));
+    let mut task_vec = Vec::new();
+    let bollingerbands = bollingerband(20, 2.0, &alldata.rt_price_30m_vec, &filtered_data_3rd).await?;
+    for element in filtered_data_3rd {
+        let mut rt_30m_vec: Vec<RealtimePriceData> = Vec::new();
+        let mut bb_vec: Vec<BollingerBandData> = Vec::new();
+        let rt_price_30m_vec_c: Vec<(String, Vec<RealtimePriceData>)> = alldata.rt_price_30m_vec.clone();
+        let bollingerbands_c = bollingerbands.clone();
+        let filtered_data_4th_arc_c = Arc::clone(&filtered_data_4th_arc);
+        task_vec.push(tokio::spawn(async move {
+            let rt_30m_option = rt_price_30m_vec_c
+                .iter()
+                .position(|x| *x.0 == element.symbol);
+            let bb_option_30m = bollingerbands_c.iter().position(|x| x.0 == element.symbol);
+
+            if rt_30m_option.is_some() && bb_option_30m.is_some() {
+                rt_30m_vec = rt_price_30m_vec_c[rt_30m_option.unwrap()].1.clone();
+                bb_vec = bollingerbands_c[bb_option_30m.unwrap()].1.clone();
+                let server_epoch = server_epoch().await;
+                if rt_30m_vec.len() >= 6 && bb_vec.len() >= 6 && rt_30m_vec.last().unwrap().close_time > server_epoch {
+                    let bb_search_result = bb_vec.binary_search_by_key(
+                        &rt_30m_vec.last().unwrap().close_time,
+                        |BollingerBandData {
+                            sma,
+                            upperband,
+                            lowerband,
+                            close_time,
+                         }| *close_time,
+                    );
+                    if bb_search_result.is_ok() {
+                        if bb_vec[bb_search_result.unwrap()-1].lowerband > rt_30m_vec[rt_30m_vec.len()-2].low_price || 
+                        bb_vec[bb_search_result.unwrap()-2].lowerband > rt_30m_vec[rt_30m_vec.len()-3].low_price || 
+                        bb_vec[bb_search_result.unwrap()-3].lowerband > rt_30m_vec[rt_30m_vec.len()-4].low_price || 
+                        bb_vec[bb_search_result.unwrap()-4].lowerband > rt_30m_vec[rt_30m_vec.len()-5].low_price || 
+                        bb_vec[bb_search_result.unwrap()-5].lowerband > rt_30m_vec[rt_30m_vec.len()-6].low_price
+                        {
+                            let mut filtered_data_4th_lock = filtered_data_4th_arc_c.lock().await;
+                            let mut filtered_data = FilteredData::new();
+                            filtered_data.symbol = element.symbol.clone();
+                            filtered_data.closetime = rt_30m_vec.last().unwrap().close_time;
+                            filtered_data.current_price = rust_decimal::prelude::FromPrimitive::from_f64(rt_30m_vec.last().unwrap().close_price).unwrap();;
+                            filtered_data_4th_lock.push(filtered_data);
+                        }
+                    }
+                }
+            }
+        }));
+    }
+    try_join_all(task_vec).await?;
+
+    let final_filtered_data = filtered_data_4th_arc.lock().await.clone();
     insert_pre_suggested_coins(3, false, &final_filtered_data, &alldata).await;
 
     Ok(())